Ignition distributor



Oct. 30, 1962 E. c. BETTONI IGNITION DISTRIBUTOR 2 Sheets-Sheet 1 FiledJuly 1, 1960 mmvron EUGE N E C. BETTONI 09m.

ATTORNEYS Oct. 30, 1962 E. c. BETTONI 3,060,749

IGNITION DISTRIBUTOR Filed July 1, 1960 2 Sheets-Sheet 2 FIG.3.

INVENTOR.

EUGENE C BETTONI Maw ATTORNEYS United States Patent 3,060,749 IGNITIONDISUTOR Eugene C. Bettoni, Birmingham, Mich, assignor to HolleyCarburetor Company, Van Dyke, Mich, a corporation of Michigan Filed July1, 1960, Ser. No. 40,446 3 Claims. ((11. 73-509) The present inventionrelates to an ignition distributor and represents an improvement overthe ignition distributor shown in Johnson Patent 2,905,162. Basically,the distributor is responsive to engine speed and an engine vacuum suchfor example as manifold vacuum, to efiect a timing adjustment of thedistributor.

It is an object of the present invention to provide in mechanism of thecharacter described a rotary construction including a centrifugal weightmovable radially of an axis of rotation against spring means to aposition determined by its speed of rotation, said centrifugal weightserving as a mounting for an expansible chamber responsive to an enginevacuum condition, the chamber including a movable wall mechanicallyconnected to means for effecting a timing adjustment of the distributorincluding special sealing means.

It is a further object of the present invention to provide mechanism ofthe character described provided with means for effectively preventingleakage so as to render the device at all times fully responsive tovariations in engine vacuum conditions.

More specifically, it is an object of the present invention to provide acentrifugal member slidable on a r-adially extending transfer shaftincluding an expansible chamber having a movable wall, means connectedto the movable wall for effecting adjustment of the ignitiondistributor, and a pair of diaphragms connected to said transfer shaft,one of said diaphragms being connected to said centrifugal member, theother of said diapbragms being connected to said means.

It is a further object of the present invention to provide in aconstruction as described in the preceding paragraph, a main pressureresponsive chamber slidable on a shaft, and a pair of balancing sealedchambers connected to said main chamber by clearance. Other objects andfeatures of the invention will become apparent as the descriptionproceeds, especially when taken in conjunction with the accompanyingdrawings, illustrating a preferred embodiment of the invention, wherein:

FIGURE 1 is a plan view of the ignition distributor.

FIGURE 2 is a sectional view on the line 2--2, FIG- URE 1.

FIGURE 3 is a greatly enlarged fragmentary sectional View also taken onthe line 2--2, FIGURE 1.

The distributor which may be of the conventional design disclosed inJohnson 2,905,162, includes a rotary shaft on the upper end of which isrotatably mounted a cam 12. The cam 12 is rotated at shaft speed but themechanism disclosed herein effects angular adjustment of the camrelative to the shaft to control spark advance. Specifically, theangular position of the cam 12 relative to the shaft 10 is controlled byshaft speed and by a vacuum condition variable in accordance with engineoperation such for example as manifold vacuum.

In order to accomplish the foregoing there is provided a housing 14enlarged to include a'chamber 16 which receives centrifugal and pressureresponsive mechanism as will subsequently be described.

Intersecting the shaft 10 in the chamber 16 is a transfer shaft 18. Theshaft 10 has an axially extending passage 20 including one or moreradial passages 22 adapted to connect the axial passage 20 with anannular chamber 24 connected by a passage 26 to a fitting 28 to which isconnected a conduit leading to the engine intake manifold.

The transfer shaft 18 includes an elongated axially extending passage 30and a short radial passage 32 which communicates with the axiallyextending passage 20 of the shaft 10. Movable devices 34 are slidablymounted on the transfer shaft 18 and include laterally extending arms 36including forwardly extending portions 38 provided with pins 40 receivedin elongated slots at the ends of cam adjusting arms 42. It will beapparent that if the devices 34 as seen in FIGURE 1, move away from eachother from the illustrated position, the cam adjusting arm device 42will rotate in a clockwise direction.

Referring now to FIGURE 3, there is illustrated the mechanism whicheffects movement of the devices 34.

The radially extending transfer shaft 18 is provided at its outer endswith radially extending flanges 44 and a reduced pilot portion 46 whichis received in a cylindrical seat 48 provided at the inner end of aguide shaft 50. The shaft 50 includes at its inner end a radiallyextending flange 52 which is connected to the flange 44 by suitablefastening means such as the rivets 54. The flanges 44 and 52 receivebetween them the inner edge of an annular flexible diaphragm 56.

The movable devices 34 each comprise a housing portion 58 to which thelaterally extending arm 36 is con nected, and a housing portion 60. Thehousingportion 60 has a peripheral flange 62 bent over a peripheralflange 64 to clampingly engage the outer edge ofthe annular flexiblediaphragm '56. The housing portion 58 is provided with an atmosphereport 66 and the construction just described defines a sealed expansiblevacuum chamber 68.

Also slidable on the guide shaft 50 is a centrifugal weight 70 includinga recess 72 closed by a flexible diaphragm 74. The outer edge of theannular flexible diaphragm 74 is clamped to the centrifugal weight by anannular cover 76 and the inner end of the flexible diaphragm 74 isclamped between plates 78 carried by the housing portion 60 of themovable device 34. A compression spring 79 engages one of the plates 78and urges the movable device 34 to the left as seen in FIGURE 3,relative to the centrifugal weight 70. The cover 76 includes an enlargedannular opening 80 which connects the space 82 to atmosphere. Thediaphragm 74 defines with the recess 72 a sealed vacuum chamber 83. Theguide shaft 50 is provided with an elongated axially extending passage84 connecting with the passage-30 and provided with a radially extendingpassage 86 which extends to the interior of the chamber defined by therecess 72.

At its outer end the guide shaft 50 is provided with an element 88including a plug portion 90 which closes and seals the outer end of thepassage 84. The element 88 includes a radially extending flange 92 whichcooperates with a radially extending flange 94 at the outer end of theguide shaft 50 to clampingly engage the inner edge of an annularflexible diaphragm 96. The outer edge of the flexible diaphragm 96 isclamped by a bent over flange" portion 98 on the centrifugal weight 70so as to define a sealed chamber 100. v v

The element 88 includes a threaded end portion 102 carrying a nut 104.which supports a spring seat 106. Extending between the spring seat 106and shoulders 108 and 110 on the centrifugalweight are coil compressionsprings 112 and 114 respectively.

In operation the position of the centrifugal weight -70 is determined bythe speed of rotation of the shaft 10, the centrifugal force at anyparticular speed of course being balanced by the forces of the springs112 and 114. The application of manifold vacuum to the chamber 83 tendsto draw the movable device 34 to the right as seen 3, to a positiondetermined by the compression of the spring '79. V

In order for the centrifugal weight 70 and the movable device 3 4'tomoveinstantly to the proper position on the guide shaft 50 and thetransfer shaft 18, it is necessary to provide a free sliding fit for themovable elements.

This in turn necessarily results in leakage between the chamber 83 andatmosphere. In accordance with the present invention the sources ofpossible leakage are caused to lead into independent and opposed sealedvacuum chambers so that the full manifold vacuum is always available toefliect adjustment of the movable device 34 relative to the centrifugalweight 70. With this construction a very free sliding fit for thecentrifugal weight and centrifugal device on the guide shaft 50 may bepermitted, and in fact, if desired, the parts may be deliberately shapedso as to provide for communication between the chambers 83, 68 and 100.

'It is of course apparent that air flow along the guide shaft 50 fromthe chamber 83 to the chamber 100 will result in evacuation of thechamber 100 to a sub-atmospheric pressure existing instantaneouslywithin the cham ber 83, Similarly, leakage flow of air along'the guideshaft 50 from the chamber 83 into the sealed chamber 68 will result insub-atmospheric pressure within the chamber 68 equal to that existing inthe chamber 83'.

It will be observed that the flexible diaphragms 56 and 94 have the sameeffective area so that the existence of identical sub-atmosphericpressures in these chambers produces a balance so that the position ofthe centrifugal weight 70 is determined solely by speed of rotation ofthe shaft 10. The diaphragm 74 is of larger effective area than thediaphragm 56 so that the position of the movable device 34 is determinedby the difference between these areas.

The drawings and the foregoing specification constitute a description ofthe improved ignition distributor in such full, clear, concise and exactterms as to enable any person skilled in the art to practice theinvention, the scope of which is indicated by the appended claims.

What I claim as my invention is:

11.111 an engine ignition distributor, a drive shaft adapted to bedriven at a speed proportional to engine speed, a cross shaft connectedto said drive shaft and extending radially from opposite sides thereof,annular centrifugal weights freely slidable in guided relationlongitudinally on the extending portions of said cross shaft at oppositesides of said drive shaft, spring means connected between said, crossshaft and each of said weights opposing radially outward movement ofsaid weights, annular recesses at corresponding sides of said weightssurrounding said cross shaft, annular adjusting members on the extendingportions of said cross shaft and freely slidable in guided'relationthereon relative to said weights, annular flexible actuating diaphragmsconnected at their outer edges to the outer edges of said annularrecesses and connected at their inner edges to said adjusting members,said diaphragms and adjusting members closing said annular recesses anddefining therewith annular chambers surrounding said cross shaft whichare sealed except for substantial fluid flow passages provided by thefree sliding fit between said cross shaft portions, said weights andsaid adjusting members, coil compression springs in said annularchambers urging said diaphragms outwardly thereof to bias said adjustingmembers radially of said'cross shaft relative to said weights, passagemeans shafts adapted to connect said chambers to a source of enginevacuum, and flexible annular sealing diaphragms at opposite sides ofboth of said actuating diaphragms connected between said cross shaftextensions and said weig s and a j s g members,

2. In an engine ignition distributor, a drive shaft adapted to be drivenat a speed proportional to engine speed, a cross shaft connected to saiddrive shaft and extending'radially from opposite sides thereof, annularcentrifugal weights freely slidable in guided relation longitudinally onthe extending portions of said cross shaft at opposite sides of saiddrive shaft, spring means connected between said cross shaft and each ofsaid weights opposing radially outward movement of said weights, annularrecesses at the radially inner sides of said weights surrounding saidcross shaft, annular adjusting members on the extending portions of saidcross shaft at the inner sides of said weights and freely slidable inguided relation thereon relative to said weights, annular flexibleactuating diaphragms connected at their outer edges to the outer edgesof said annular recesses and connected at their inner edges to saidadjusting members, said diaphragms and adjusting members closing saidannular recesses and defining therewith annular chambers surroundingsaid cross shaft which are sealed except for substantial fluid fiowpassages provided by the free sliding fit between said cross shaftportions, said weights and said adjusting members, coil compressionsprings in said annular chambers urging said diaphrigms outwardlythereof to bias said adjusting members radially inwardly relative tosaid weights, passage means in shafts adapted to connect said chambersto a source of engine vacuum,

' 1 and flexible annular sealing diaphragms at opposite sides of both ofsaid actuating diaphragms connected between said cross shaft extensionand said weights and adjusting members.

3. In an engine ignition distributor, a' drive shaft adapted to bedriven at a speed proportional to engine speed, across shaft connectedto said drive shaft and extending radially from opposite sides thereof,annular centrifugal weights freely slidable in guided relationlongitudinally on the extending portions of said cross shaft at oppositesides of said drive shaft, spring means connected between said crossshaft and each of said weights opposing radially outward movement ofsaid Weights, annular recesses at corresponding sides of said weightssurrounding said cross shaft, annular adjusting members on the extendingportions of said cross shaft and freely slidable in guided relationthereon relative to said weights, annular flexible actuating diaphragmsconnected at their outer edges to the outer edges of said annularrecesses and connected at their inner edges to said adjusting members,said diaphragms and adjusting members closing said annular recesses anddefining therewith annular chambers surrounding said cross shaft whichare sealed except for substantial fluid flow passages provided by thefree sliding fit between said cross shaft portions, said weights andsaid adjusting members, coil compression springs in said annularchambers urging said diaphragms outwardly thereof to bias said adjustingmembers radially of said cross shaft relative to said weights, passagemeans in shaft-s adapted to connect said chambers to a source of enginevacuum, and flexible annular sealing diaphragms of equal area atopposite sides of both of said actuating diaphragms con? nected betweensaid cross shaft extensions and said weights and adjusting members, 7

References Cited in the file of this patent UNITED STATES PATENTS2,145,575 Zwickl Jan. 31, 1939 2,380,983 Mock Aug. 7, 1945 2,602,627Britton July 8, 1952 2,842,971 Cornell July 15, 1958 2 Joh on S pt- 952

